The present invention relates to an input device and, more particularly, to a key input device exchangeably connectable to a programmable electronic calculator.
A conventional programmable calculator can program any desired programs suitable for specific purposes. Since, conventionally, the same key input device is connected to the calculator, there are always switches on the dey input device that are not required for carrying out a desired operation. The keyboard input operation is somewhat difficult because the necessary key switches must be distinguished from the plurality of key switches that are not required.
Therefore, it is desired to provide an improved key input device suitable for a programmable calculator.